NICHD is collaborating with Dr. Cecilia Pyper, Oxford University, to assess the impact of psychosocial stress on female fecundity as measured by time-to-pregnancy. Specifically, NICHD will build a stress component into Dr. Pyper's currently ongoing Oxford Conception Study (OCS). The OCS is a three-arm randomized clinical trial designed to evaluate whether or not daily feedback from a digital fertility monitor increases the conception rate among women desiring pregnancy. Women enrolled in the OCS are followed for up to six months as they try to conceive. During this time, women send daily diary information, a mood questionnaire and data from their fertility monitor to the investigators on a monthly basis. Three-month and six-month cumulative pregnancy rates will be compared for the women in each of the three groups. NICHD has added a component to the Oxford Conception Study (OCS) with the expressed intent of measuring stress and its impact on female fecundity among newly enrolled women in the OCS (approximately 400 women). The NICHD's research objectives are: 1) to evaluate the effect of perceived psychosocial stress on time to pregnancy; 2) to evaluate the effect of physiologic stress on time to pregnancy; 3) to assess whether or not perceived psychosocial stress is associated with physiologic stress; and 4) to assess whether or not underlying anxiety and depression, social support, locus of control, or self-esteem confound or modify the relation between perceived psychosocial stress or physiologic stress and time-to-pregnancy. Saliva samples will be analyzed for two biomarkers of stress, viz., cortisol and alpha amylase. The Cohen?s Perceived Stress Scale will be used to measure perceived psychosocial stress. Several other psychosocial instruments will be administered at baseline to allow us to assess whether or not they confound or modify the relation between physiologic stress or perceived psychosocial stress and time-to-pregnancy.